Re: [PATCH v13 1/8] save/load cpu runstate

Eric Blake
2013-02-28T21:13:36Z

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On 02/28/2013 05:13 AM, Hu Tao wrote:
> This patch enables preservation of cpu runstate during save/load vm.
> So when a vm is restored from snapshot, the cpu runstate is restored,
> too.

What happens if a management app wants to override the runstate when
restoring the domain? I can think of several useful scenarios:

1. management app pauses the guest, then saves domain state and other
things (management state, or disk clones), then resumes the guest.
Later, the management wants to revert to the saved state, but have the
guest running right away. I guess here, knowing that the guest was
saved in a paused state doesn't hurt, since the management app can
resume it right away.

2. management app saves domain state of a live guest, then copies that
state elsewhere. In its new location, the management app wants to
investigate the state for forensic analysis - so even though the guest
remembers that it was running, management wants to start it paused.
Here, it is important that there must not be a window of time where the
guest can run, otherwise, the results are not reproducible.

--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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